What brake pipe reduction must the engineer make during a Class I test?

During a Class I test, the engineer is required to make a brake pipe reduction of 20 PSI. This specific reduction amount is critical because it is part of the standard operating procedure for testing the effectiveness of the air brake system on the train.

The purpose of this brake pipe reduction is to ensure that the air brake system can respond correctly to a change in pressure, which is essential for safe train operation. A reduction of 20 PSI is sufficient to evaluate the response of the system, allowing the engineer to observe whether the brakes apply properly and if there are any leaks or issues within the brake system.

Understanding this standard is crucial for train engineers and crew members, as it ensures that they are compliant with safety regulations and that the trains they operate can stop effectively in various conditions. Hence, the requirement for a 20 PSI reduction during a Class I test is a vital component of maintaining operational integrity and safety on the railways.